On Wed, Sep 24, 2014 at 06:52:41PM +0400, Vladimir Davydov wrote: > memcg_can_account_kmem() returns true iff > > !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) && > memcg_kmem_is_active(memcg); > > To begin with the !mem_cgroup_is_root(memcg) check is useless, because > one can't enable kmem accounting for the root cgroup (mem_cgroup_write() > returns EINVAL on an attempt to set the limit on the root cgroup). > > Furthermore, the !mem_cgroup_disabled() check also seems to be > redundant. The point is memcg_can_account_kmem() is called from three > places: mem_cgroup_salbinfo_read(), __memcg_kmem_get_cache(), and > __memcg_kmem_newpage_charge(). The latter two functions are only invoked > if memcg_kmem_enabled() returns true, which implies that the memory > cgroup subsystem is enabled. And mem_cgroup_slabinfo_read() shows the > output of memory.kmem.slabinfo, which won't exist if the memory cgroup > is completely disabled. > > So let's substitute all the calls to memcg_can_account_kmem() with plain > memcg_kmem_is_active(), and kill the former. > > Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> Yes, the two checks look indeed redundant. Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>